1. Field of the Invention
The present invention relates to a test jig, and more particularly, to a test jig implementing a tensile test for an ultrasonic-welded portion only using an electrode lead without use of a cell.
2. Description of the Related Art
In general, a secondary battery is used in the form of a unit cell and a plurality of unit cells are electrically connected to be used in a form of a battery module. For instance, small-sized devices such as mobile phones may work for a predetermined time with the output and capacity of a unit cell, whereas medium- or large-sized devices such as laptop computers, portable DVDs, small personal computers (PCs), electric vehicles, and hybrid vehicles require a battery module consisting of a plurality of unit cells due to limitations in their outputs and capacities.
The secondary battery is manufactured through a cell assembling process and a battery activation process. In the battery activation process, a cell is mounted on a predetermined jig for a smooth flow of electric current and conditions required for activation, or a tensile test is performed on an ultrasonic-welded portion of an electrode lead of the cell.
Meanwhile, since ultrasonic welding is performed for multiply connecting between a bus bar of the secondary battery and an electrode lead of the cell, the tensile test is performed on the ultrasonic-welded portion, wherein a destructive inspection is performed to measure a tensile force due to the nature of the welding.
Specifically, the tensile test is performed on the ultrasonic-welded portion, as illustrated in FIGS. 1 and 2, in a state where upper and lower jigs 20 and 30 are coupled to an upper part and a lower part of a cell 10 provided with an electrode lead 11, respectively.
However, the secondary battery according to the related art can not reuse the cell provided with the electrode lead 11, which has been subjected to the tensile test, thereby remarkably increasing unnecessary cost.